Re: [PATCH v1 1/5] MdePkg/BaseLib: Introduce new SpeculationBarrier API

["Gao, Liming" <liming.gao@intel.com>]

Reviewed-by: Liming Gao <liming.gao@intel.com>

> -----Original Message-----
> From: Wu, Hao A
> Sent: Friday, December 21, 2018 11:11 AM
> To: edk2-devel@lists.01.org
> Cc: Wu, Hao A <hao.a.wu@intel.com>; Ard Biesheuvel <ard.biesheuvel@linaro.org>; Leif Lindholm <leif.lindholm@linaro.org>; Gao,
> Liming <liming.gao@intel.com>; Kinney, Michael D <michael.d.kinney@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>; Laszlo Ersek
> <lersek@redhat.com>
> Subject: [PATCH v1 1/5] MdePkg/BaseLib: Introduce new SpeculationBarrier API
> 
> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1417
> 
> X86 specific BaseLib API AsmLfence() was introduced to address the Spectre
> Variant 1 (CVE-2017-5753) issue. The purpose of this API is to insert
> barriers to stop speculative execution. However, the API is highly
> architecture (X86) specific, and thus should be avoided using across
> generic code.
> 
> To address this issue, this patch will add a new BaseLib API called
> SpeculationBarrier(). Different architectures will have different
> implementations for this API.
> 
> For IA32 and x64, the implementation of SpeculationBarrier() will
> directly call AsmLfence().
> 
> For ARM and AARCH64, this patch will add a temporary empty implementation
> as a placeholder. We hope experts in ARM can help to contribute the actual
> implementation.
> 
> For EBC, similar to the ARM and AARCH64 cases, a temporary empty
> implementation is added.
> 
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Hao Wu <hao.a.wu@intel.com>
> ---
>  MdePkg/Library/BaseLib/BaseLib.inf              |  5 +++
>  MdePkg/Include/Library/BaseLib.h                | 15 +++++++++
>  MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c | 30 ++++++++++++++++++
>  MdePkg/Library/BaseLib/Ebc/SpeculationBarrier.c | 30 ++++++++++++++++++
>  MdePkg/Library/BaseLib/X86SpeculationBarrier.c  | 32 ++++++++++++++++++++
>  5 files changed, 112 insertions(+)
> 
> diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf
> index b84e58324c..d195c5417b 100644
> --- a/MdePkg/Library/BaseLib/BaseLib.inf
> +++ b/MdePkg/Library/BaseLib/BaseLib.inf
> @@ -336,6 +336,7 @@
>    X86DisablePaging32.c
>    X86RdRand.c
>    X86PatchInstruction.c
> +  X86SpeculationBarrier.c
> 
>  [Sources.X64]
>    X64/Thunk16.nasm
> @@ -515,6 +516,7 @@
>    X86DisablePaging32.c
>    X86RdRand.c
>    X86PatchInstruction.c
> +  X86SpeculationBarrier.c
>    X64/GccInline.c | GCC
>    X64/Thunk16.S | XCODE
>    X64/SwitchStack.nasm| GCC
> @@ -543,12 +545,14 @@
>    Ebc/CpuBreakpoint.c
>    Ebc/SetJumpLongJump.c
>    Ebc/SwitchStack.c
> +  Ebc/SpeculationBarrier.c
>    Unaligned.c
>    Math64.c
> 
>  [Sources.ARM]
>    Arm/InternalSwitchStack.c
>    Arm/Unaligned.c
> +  Arm/SpeculationBarrier.c
>    Math64.c                   | RVCT
>    Math64.c                   | MSFT
> 
> @@ -582,6 +586,7 @@
>  [Sources.AARCH64]
>    Arm/InternalSwitchStack.c
>    Arm/Unaligned.c
> +  Arm/SpeculationBarrier.c
>    Math64.c
> 
>    AArch64/MemoryFence.S             | GCC
> diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
> index 8cc086983d..1eb842384e 100644
> --- a/MdePkg/Include/Library/BaseLib.h
> +++ b/MdePkg/Include/Library/BaseLib.h
> @@ -5111,6 +5111,21 @@ CpuDeadLoop (
>    VOID
>    );
> 
> +
> +/**
> +  Uses as a barrier to stop speculative execution.
> +
> +  Ensures that no later instruction will execute speculatively, until all prior
> +  instructions have completed.
> +
> +**/
> +VOID
> +EFIAPI
> +SpeculationBarrier (
> +  VOID
> +  );
> +
> +
>  #if defined (MDE_CPU_IA32) || defined (MDE_CPU_X64)
>  ///
>  /// IA32 and x64 Specific Functions.
> diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c
> new file mode 100644
> index 0000000000..8a6165a102
> --- /dev/null
> +++ b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c
> @@ -0,0 +1,30 @@
> +/** @file
> +  SpeculationBarrier() function for ARM.
> +
> +  Copyright (C) 2018, Intel Corporation. All rights reserved.<BR>
> +
> +  This program and the accompanying materials are licensed and made available
> +  under the terms and conditions of the BSD License which accompanies this
> +  distribution.  The full text of the license may be found at
> +  http://opensource.org/licenses/bsd-license.php.
> +
> +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
> +  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +
> +/**
> +  Uses as a barrier to stop speculative execution.
> +
> +  Ensures that no later instruction will execute speculatively, until all prior
> +  instructions have completed.
> +
> +**/
> +VOID
> +EFIAPI
> +SpeculationBarrier (
> +  VOID
> +  )
> +{
> +}
> diff --git a/MdePkg/Library/BaseLib/Ebc/SpeculationBarrier.c b/MdePkg/Library/BaseLib/Ebc/SpeculationBarrier.c
> new file mode 100644
> index 0000000000..8fa4c204f8
> --- /dev/null
> +++ b/MdePkg/Library/BaseLib/Ebc/SpeculationBarrier.c
> @@ -0,0 +1,30 @@
> +/** @file
> +  SpeculationBarrier() function for EBC.
> +
> +  Copyright (C) 2018, Intel Corporation. All rights reserved.<BR>
> +
> +  This program and the accompanying materials are licensed and made available
> +  under the terms and conditions of the BSD License which accompanies this
> +  distribution.  The full text of the license may be found at
> +  http://opensource.org/licenses/bsd-license.php.
> +
> +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
> +  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +
> +/**
> +  Uses as a barrier to stop speculative execution.
> +
> +  Ensures that no later instruction will execute speculatively, until all prior
> +  instructions have completed.
> +
> +**/
> +VOID
> +EFIAPI
> +SpeculationBarrier (
> +  VOID
> +  )
> +{
> +}
> diff --git a/MdePkg/Library/BaseLib/X86SpeculationBarrier.c b/MdePkg/Library/BaseLib/X86SpeculationBarrier.c
> new file mode 100644
> index 0000000000..03deca8489
> --- /dev/null
> +++ b/MdePkg/Library/BaseLib/X86SpeculationBarrier.c
> @@ -0,0 +1,32 @@
> +/** @file
> +  SpeculationBarrier() function for IA32 and x64.
> +
> +  Copyright (C) 2018, Intel Corporation. All rights reserved.<BR>
> +
> +  This program and the accompanying materials are licensed and made available
> +  under the terms and conditions of the BSD License which accompanies this
> +  distribution.  The full text of the license may be found at
> +  http://opensource.org/licenses/bsd-license.php.
> +
> +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
> +  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#include <Library/BaseLib.h>
> +
> +/**
> +  Uses as a barrier to stop speculative execution.
> +
> +  Ensures that no later instruction will execute speculatively, until all prior
> +  instructions have completed.
> +
> +**/
> +VOID
> +EFIAPI
> +SpeculationBarrier (
> +  VOID
> +  )
> +{
> +  AsmLfence ();
> +}
> --
> 2.12.0.windows.1